ANNUAL RECORD 



OF 



SCIENCE AND INDUSTRY. 



187 2. 



A. MATHEMATICS AND ASTRONOMY. 



OX THE TRUE TEMPERATURE OF THE SUJST. 



At a recent meeting of the French Academy Mons.Vicaire 

 called attention to the state of our knowledge in regard to 

 the temperature of the sun. The highest estimate of this 

 temperature is about 18,000,000 Fahr., by Father Secchi ; 

 the lowest from 2662 to 3201 Fahr., by Pouillet ; and other 

 physicists have given varying estimates, generally under 

 200,000 Fahr. Perhaps the most surprising feature con- 

 nected with these estimates is that the two extreme results 

 viz., those of Secchi and Pouillet have both been derived 

 from observations on radiation made by means of apparatus 

 which is essentially identical in principle. M.Vicaire showed 

 that the difference in these results has arisen, not from any 

 thing in the observations themselves, but from the fact that 

 Father Secchi has made his reductions by means of an erro- 

 neous formula. Correcting this error, he finds for the tem- 

 perature of the sun, from Father Secchi's observations, 2548 

 Fahr. a result almost identical with that of Pouillet; and 

 he finally arrives at the conclusion that the temperature of 

 the solar surface is entirely comparable with that of terrestrial 

 flames, and is certainly less than 5500 Fahr. 



In the discussion which followed the reading of M.Vicaire's 

 paper, the president of the Academy called attention to Sir 



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